Belt sander



R. E. GRON-KE v June 20, 1967 BELT SANDER 2 Sheets-Sheet 1 Filed March11, 1964 INVENTOR. RONALD E GQONKE United States Patent 3,325,948 BELTSANDER Ronald E. Granite, Des Plaines, 111., assignor to SkilCorporation, Chicago, 111., a corporation of Delaware Filed Mar. 11,1964, Ser. No. 351,134 3 Claims. (Cl. 51-441) This invention relatesgenerally to portable, powered belt sanders, and more particularly tonew and improved dust pickup and motor cooling construction for suchsanders.

It is a primary object of the present invention to provide a belt sanderhaving new and improved dust pickup and motor cooling construction,which construction contributes to balanced design of the sander therebymaking the same easy to manipulate or maneuver by hand.

It is a further object of the present invention to provide in a beltsander of the type described, a double vane fan and associated housingconstruction of new and improved design for effectively cooling thesander motor and collecting dust at the vicinity of one of the rollersof the sander.

It is another object of the present invention to provide a belt sanderin accordance with the above mentioned objects and including further ahousing having a vertical fiat side coplanar with an edge of the sandingbelt so as to adapt the belt sander for sanding marginal portions ofsurfaces which are bordered by walls or ledges, for examle. P These andother objects and advantages of the invention will become apparent fromthe following specification disclosing a preferred embodiment of theinvention which is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of one form of the belt sander of thisinvention;

FIG. 2 is a rear elevational view of the sander with a portion of thesame broken away so as to show a passageway associated with the dustpickup construction;

FIG. 3 is an enlarged fragmentary section taken generally along line 33of FIG. 1;

FIG. 4 is an enlarged perspective view of a member forming an end wallof a motor enclosing portion of the sander housing;

FIG. 5 is a section taken along line 5-5 of FIG. 4; and

FIG. 6 is a section taken along line 66 of FIG. 3.

Referring now to the drawings, the belt sander of this inventionincludes a housing characterized by a lower elongated portion 10 and anupper, cylindrical, transversely extending portion 12. Housing portion10 includes suitable means rotatably supporting transversely thereof apair of parallel spaced rollers 14 and :16. Lower housing portion 10also includes a shoe 18 mounting a pad 20 which supports the lower runof a flexible sanding belt 22 trained over both rollers 14, 16, whichbelt has a width substantially the same as the length of the rollers.Housing portion 16 mounts a fixed fiat guide bar 24 which engages oneedge of belt 22 for locating the same laterally of the sander duringinstallation. Front roller 16 is resiliently supported in housingportion 10 by means including suitable spring means (not shown) forurging this roller forwardly so as to maintain belt 22 tight. The meansfor supporting roller 16 include a snap bracket 26 mounting roller 16 soas to permit the latter to be snapped rearwardly for belt removal andreplacement. The means supporting belt 22 are described for purposes ofillustration only as this construction of itself forms no part of thepresent invention; other suitable means may be provided for supporting asanding belt such as belt 22.

Lower housing portion 19 is open at one side thereof 3,325,948 PatentedJune 20, 1967 (the near side as seen in FIG. 1), which open side isdefined by a housing edge 28 which is contained in a vertical plane withcommon ends of rollers 14, 116 being coplanar with housing edge 28. Theother side of lower housing portion 10 is closed by a wall 29 whichserves, among other things, to support the shafts rotatably mountingrollers 14 and 16.

Cylindrical housing portion 12 includes an end wall 30 (FIG. 3) providedwith a plurality of suitably spaced vents 32 (FIG. 2) which extend intothe interior of housing portion 12. Wall 30 is secured to housingportion 12 by a number of fasteners 33 (FIG. 2). The other end ofcylindrical portion 12 is defined by a circular plate 34, which plateincludes a number of integral lugs 36 (FIG. 4) defining arcuateshoulders 38 which fit within the end of cylindrical housing portion 12.Plate 3-4 is secured to housing portion 12 by a number of fasteners 40(FIGS. 1 and 2) extending through suitable apertures in ears 42 of plate34 and threadingly engaging suitable threaded bores (not shown) inhousing portion 12. Lugs 36 define with the end of housing portion 12 aplurality of openings 44 (FIG. 3) which permit discharge of the airflowfor cooling the motor as will be explained hereinbelow. Plate 34includes a planar exterior surface having a number of parallelhorizontally extending recesses 46 provided therein. These recesses donot extend through plate 34; they are provided for ornamentationpurposes only. The outer face of plate 34 characterized by theserecesses is coplanar with edge 28 of lower housing portion 10 for apurpose to be explained hereinbelow.

An electric motor 48 of suitable construction has its stator secured inhousing portion 12 by fasteners 49. The motor includes a rotor shaft 50having one end thereof supported in a bearing 52, which bearing ismounted in a central recess 54 formed integrally with plate 34 on theinside center portion thereof. The other end of shaft 50 is rotatablysupported in a bearing 56, this bearing being supported in an aperture58 formed in end wall 30 of housing portion 12. Motor 48 includes theusual commutator 60 having brushes 62 held against the same byassociated springs 64, the brushes and springs being mounted in brushholders 66 received in suitable cavities in housing portion 12 and heldtherein by fasteners 68.

The end of motor shaft 50 adjacent bearing 56' extends outwardly ofhousing wall 30 and non-rotatably mounts a drive wheel 70 includingfixed-together parts 70a and 70b. Wheel 70 includes on its outer surfacea number of parallel spaced grooves engaging complementary shaped ribson the inside surface of a drive belt 72. Drive belt 72 is trained overa driven wheel 74, which driven wheel is provided on its exterior withspaced axially extending grooves for complementary engagement with theribs on belt 72 so as to prevent slippage with the latter. Driven wheel74 includes fixed together parts 74a, 74b, part 74b being non-rotata'blymounted on one end of a shaft 78. Shaft 78 is journaled at its midpointin a sleeve 80, which sleeve is supported in a bore 82 formed in ahousing wall 84, which wall cooperates with a shell member 85 to definean enclosure for wheels 70, 74 and belt 72. The other end of shaft 78 isjournaled in a sleeve 86 mounted in an opening 88 formed in lowerhousing wall 29. Shaft 78 includes an annular series of teeth 90, whichteeth are in meshing engagement with complementary shaped teeth on agear 91. Gear 91 is fixedly mounted on a shaft 92 which is journaled inbearings 93, 94 supported in openings in respective walls 29, 84. Shaft92 is fixed to and supports roller 14. It should be apparent thatenergizing of motor 48 serves to rotate roller 14 thereby to drive belt22. Belt 22 is driven in a direction so that the lower run thereof movesrearwardly of housing 10, i.e. toward roller 14.

Cylindrical housing portion 12 includes a rearwardly extending pistongrip portion 96 supporting a trigger 98. Pistol grip portion 96 alsoserves as attaching means for one end of an electrical cord 100, whichcord contains the usual lead wires extending to the electric motorthrough a switch (not shown) operated by trigger 98. Housing portion 12also includes an auxiliary or forward handle 102, thereby adapting thebelt sander to be grasped by both hands of an operator.

A double vane fan 104 is mounted on an enlarged portion 50a of shaft 50adjacent the end thereof journaled in sleeve 52. Fan 104 includes acentral web 105 having formed onone side thereof a first set of radiallyextending vanes 106 and having formed on the other side thereof a secondset of radially extending vanes 108. End plate 34 includes an annularwall 110 which serves as a supporting surface for an annular baffleplate 112, the baflie plate being secured to wall 112 at marginalportions of the former by suitable fastening means (not shown). Annularbaffie plate 112, which includes a central opening 112a, defines withthe inside walls of plate 34 a dust collecting chamber 114. Annularbaffle plate 112 also defines in housing portion 12 a motor enclosingchamber 116. A second annular plate 118 is secured in housing portion 12in close parallel spaced relation with the web of fan 104. Baflle plate118 includes a central opening 118a. Web 105 of fan 104 defines withbaffle plates 112, 118 a pair of fan spaces 119a, 11%.

Referring now to FIGS. 46, plate 34 includes an integral, upstandingportion or stack 120 defining a vertically extending dischargepassageway 122 which opens at one end thereof into fan space 119a andwhich opens at the other end thereof at the top of stack 120 at anenlarged portion 122a. Stack 120 is externally threaded as at 124 forthreading engagement with a collar 126 rotatably attached to one end ofa conduit 128, the end of which conduit extends to a dust collecting bag130. It will be understood that collar 126 serves as a means fordetachably securing conduit 128 and the dust bag to stack 120 forcommunicating passageway 122 with the interior of the dust collectingbag.

A shell 132 is secured in overlying relation on the rear end of housingportion by fasteners 133 (FIG. 2), which shell includes a resilient pad134 extending transversely of the sander housing for supporting the rearend thereof. Shell 132 defines with the exterior of housing 10 at therear portion thereof a passageway 136 opening at one end thereof in thevicinity of roller 14 just rearwardly of the latter. It will beunderstood that this opening adjacent roller 14 extends completely alongthe length of the same. Passageway 136 funnels into a reduced tubelikeportion 132a which interfits with a complementary shaped tubular portion138 integral with end wall 34. Tubular portion 138 includes a passageway138a (FIG. 3) communicating passageway 136 with dust collecting chamber114.

During operation of the belt sander for performing a sanding operation,fan 104 causes a flow of air through passageways 136, 138a, dustcollecting chamber 114, opening 112a, fanspace 119a, passageway 122 andconduit 128 into bag 130. This flow of air picks up dust or the likecarried rearwardly by the lower run of belt 22 and carries the dust intobag 130. Rotation of fan 104 also causes a flow of air through ventopenings 32, motor enclosing chamber 116, opening 118a, fan space 1191)and outwardly through openings 44. This flow of air cools electric motor48. Thus, double vane fan 104 se-rvesboth to cool motor 48 and collectdust formed by the action of the sanding belt.

It will be appreciated that the location of fan 104 and its associatedhousing construction on the side of the belt sander housing opposite theside thereof supporting the drive means between the motor and one of therollers serves to balance the belt sander thereby making the lattereasier to manipulate or maneuver. As the outer surface of plate 34 iscoplanar with lower housing edge 28 and common ends of rollers 14 and 16which support belt 22, the sander of this invention may be used to sandmarginal portions of a surface bordered by a ledge or wall for example.In other words, in sanding a floor, for example, the edge or margin ofthe floor may be sanded as the sander has no overhanging parts along theopen side thereof so as to prevent the sander from being brought intocontact with a baseboard or wall bordering the floor being sanded.

It should be noted that baffle plate 112 acts to improve the airflowfrom the dust collecting chamber so as to improve the efficiency of thefan in collecting dust and forcing the same into bag 130.

While the invention has been shown in but one form it will be obvious tothose skilled in the art that it is not to be so limited. On thecontrary the invention is susceptible to various forms and modificationswithout departing from the spirit and scope of the appended claims.

I claim:

1. In a belt sander, in combination, an elongated housing having meanssupporting a pair of rollers transversely of the housing and in parallelspaced relation, said housing including a transversely extending motorenclosing portion which is provided with vents in one end thereof, saidhousing having a vertical planar side with common ends of said rollersand theother end of said motor enclosing portion being substantiallycoplanar with said planar side, an electric motor supported in saidmotor enclosing portion axially of the same, said motor having the endthereof adjacent said one end of the motor enclosing portion in drivingengagement with one of said rollers by means which extend along the sideof said housing opposite said planar side thereof, said housingincluding means defining a passageway opening at one end thereof in thevicinity of one of said rollers and opening at the other end thereofinto said motor enclosing portion adjacent said other end thereof, saidhousing including discharge passageway means opening into said motorenclosing portion adjacent said other end thereof, a double vane fanmounted insaid motor enclosing portion in close spaced relation withsaid other end thereof and driven by said motor for rotation about anaxis extending transversely of the housing, said fan being effective tocool said motor and to evacuate dust in the vicinity of said lastmentioned roller.

2. In a belt sander, in combination, an elongated housing having meanssupporting a pair of rollers transversely of the housing and in parallelspaced relation, said housing including a transversely extendingcylindrical portion which is provided with vents in one end thereof, anannular baffie plate mounted in said cylindrical portion perpendicularto the central axis thereof and in close spaced relation with the otherend of the cylindrical portion thereby defining a motor enclosingchamber and a dust collecting chamber, said housing having a verticalplanar side with common ends of said rollers and said other end of saidcylindrical portion being substantially coplanarwith said planar side,an electric motor supported in said motor enclosing chamber axially ofthe same, said motor having the end thereof adjacent said one end of thecylindrical portion in driving engagement with one of said rollers bymeans which extend along the side of said housing opposite said planarside thereof, said housing including means defining a passageway openingat one end thereof in the vicinity of one of said rollers and opening atthe other end thereof into said dust collecting chamber, a double vanefan in said motor enclosing chamber driven by said motor for rotationabout said axis in close spaced relation with said baffle plate, saidcylindrical portion including discharge passageway means opening intosaid motor enclosing chamber adjacent said baffle plate, said fan beingeffective to cool said motor, and said fan also being effective toevacuate dust by drawing the latter from the dust collecting chamberthrough the opening defined by the baffle plate and then into thedischarge passageway means.

3. In a motor driven belt sander of the type including dust pickupmeans, wherein the sander includes an elongated housing portionsupporting a pair of transversely extending belt carrying rollers, theimprovement which comprises, a motor and housing means enclosing andsupporting the former transversely of said elongated housing portion,which housing means has opposite ends generally coterminous with sidesof said elongated housing portion, a double vane fan carried by one endof said motor in a corresponding end of said housing means, drive meansconnecting the other end of said motor with the corresponding end of oneof said rollers, discharge passageway means opening into said housingmeans at said corresponding end thereof and vent means in the other endof the housing means, and further passageway means References CitedUNITED STATES PATENTS 8/1934 Myers 51-l70.4 4/1965 Burrows et al.51-1704 ROBERT C. RIORDON, Primary Examiner.

L. S. SELMAN, Assistant Examiner.

1. IN A BELT SANDER, IN COMBINATION, AN ELONGATED HOUSING HAVING MEANSSUPPORTING A PAIR OF ROLLERS TRANSVERSELY OF THE HOUSING AND IN PARALLELSPACED RELATION, SAID HOUSING INCLUDING A TRANSVERSELY EXTENDING MOTORENCLOSING PORTION WHICH IS PROVIDED WITH VENTS IN ONE END THEREOF, SAIDHOUSING HAVING A VERTICAL PLANAR SIDE WITH COMMON ENDS OF SAID ROLLERSAND THE OTHER END OF SAID MOTOR ENCLOSING PORTION BEING SUBSTANTIALLYCOPLANAR WITH SAID PLANAR SIDE, AN ELECTRIC MOTOR SUPPORTED IN SAIDMOTOR ENCLOSING PORTION AXIALLY OF THE SAME, SAID MOTOR HAVING THE ENDTHEREOF ADJACENT SAID ONE END OF THE MOTOR ENCLOSING PORTION IN DRIVINGENGAGEMENT WITH ONE OF SAID ROLLERS BY MEANS WHICH EXTEND ALONG THE SIDEOF SAID HOUSING OPPOSITE SAID PLANAR SIDE THEREOF, SAID HOUSINGINCLUDING MEANS DEFINING A PASSAGEWAY OPENING AT ONE END THEREOF IN THEVICINITY OF ONE OF SAID ROLLERS AND OPENING AT THE OTHER END THEREOFINTO SAID MOTOR ENCLOSING PORTION ADJACENT SAID OTHER END THEREOF, SAIDHOUSING INCLUDING DISCHARGE PASSAGEWAY MEANS OPENING INTO SAID MOTORENCLOSING PORTION ADJACENT SAID OTHER END THEREOF, A DOUBLE VANE FANMOUNTED IN SAID MOTOR ENCLOSING PORTION IN CLOSE SPACED RELATION WITHSAID OTHER END THEREOF AND DRIVEN BY SAID MOTOR FOR ROTATION ABOUT ANAXIS EXTENDING TRANSVERSELY OF THE HOUSING, SAID FAN BEING EFFECTIVE TOCOOL SAID MOTOR AND TO EVACUATE DUST IN THE VICINITY OF SAID LASTMENTIONED ROLLER.